The following data represent the muzzle velocity(in feet persecond) of shells fired from a155-mm gun. For eachshell, two measurements of the velocity were recorded using two different measuringdevices, resulting in the following data.

Observation 1 2 3 4 5 6

A 794.1 790.3 791.3 793.7 793.6 792.2

B 800.6 787.8 801.0 793.6 803,1 796.0

Construct a99% confidence interval about the population mean difference. Compute the difference as device A minus device B. Interpret your results.

The confidence interval is: ?

,

.